Recently, as a working fluid for a heat cycle system such as a refrigerant for a refrigerator, a refrigerant for an air-conditioning apparatus, a working fluid for a power generation system (such as an exhaust heat recovery power generation), a working fluid for a latent heat transport apparatus (such as a heat pipe), or a secondary cooling fluid, expectations are concentrated on hydrofluoroolefin (HFO), namely, hydrofluorocarbon (HFC) having a carbon-carbon double bond. HFO attracts attention as a working fluid having less effect on the ozone layer and less effect on global warming since the carbon-carbon double bond is likely to be decomposed by OH radicals in the air. Note that in the present specification, saturated HFC is referred to as HFC, and discriminated from HFO unless otherwise stated.
As a working fluid having not only less effect on the ozone layer and less effect on global warming but also low combustibility, there are hydrochlorofluoroolefin (HCFO) such as hydrochlorofluoropropene and chlorofluoroolefin (CFO) having a high ratio of halogen which reduces combustibility and having a carbon-carbon double bond which is likely to be decomposed by OH radicals in the air. Further, as hydrochlorofluoropropene, there is known 1-chloro-2,3,3,3-tetrafluoropropene (CClH═CF—CF3, HCFO-1224yd).
In the present specification, regarding halogenated hydrocarbon, an abbreviated name of the compound is mentioned in parentheses behind a compound name, and the abbreviated name is used instead of the compound name according to need. Further, only numeric characters and lower-case characters of alphabet behind a hyphen (-) (“1224yd” in “HCFO-1224yd”, for example) are sometimes used as the abbreviated name. Further, in 1224yd, a Z-isomer and an E-isomer which are geometric isomers exist according to positions of substituents bonded to carbon having a double bond. When the compound name or the abbreviated name of the compound is used unless otherwise stated regarding the compound with respect to which the Z-isomer and the E-isomer exist in the present specification, the Z-isomer, the E-isomer, or a mixture having an arbitrary ratio of the Z-isomer and the E-isomer is indicated. When (Z) or (E) is denoted behind the compound name or the abbreviated name of the compound, a Z-isomer or an E-isomer of each compound is indicated.
As a method of manufacturing 1224yd, Patent Reference 1 (JP-A No. 2014-513673) discloses a method in which 1,2-dichloro-2,3,3,3-tetrafluoropropane (CClH2—CFCl—CF3, HCFC-234bb) is subjected to a dehydrochlorination reaction at a temperature of 200 to 500° C. by using, as a catalyst, carbon (activated carbon) which is subjected to pretreatment such as acid cleaning, and on which alkali metal salt is supported.
However, in order to increase a conversion ratio of 234bb in the method described in Patent Reference 1, the pretreatment (acid cleaning) of carbon being the catalyst is required, and the performance of the catalyst changes greatly depending on the method of treatment, so that it takes a lot of time to adjust the catalyst including the pretreatment. Further, in the method of Patent Reference 1, an operating life of the catalyst is short, and a raw material conversion ratio is reduced greatly within 120 hours from the start of the reaction, so that it is difficult to cause a stable reaction for a long period of time, although reproduction of the catalyst is possible.
Further, the method of Patent Reference 1 uses a source gas in which an inert gas (N2 gas) is mixed in 234bb, so that a cost for the inert gas is required, and in addition to that, it is necessary to separate the inert gas from a product, which requires a cost for equipment for recovery, and the like.
Besides, in the method of Patent Reference 1, the dehydrochlorination reaction is caused at a temperature of 200 to 500° C., and in order to increase the conversion ratio of 234bb and selectivity of 1224yd, it is required to cause the reaction at a temperature in the vicinity of 400° C. For this reason, an energy cost is required, which is a problem. As described above, it cannot be said that the method described in Patent Reference 1 is an economically advantageous manufacturing method.